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1.
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A contribution to the study of electrode spaces of high-current short-duration electric discharges
The electrode spaces of high-current short-duration discharges are analyzed using the method of artificial contraction (limiting of the active surface of the electrodes). It was shown that evaporation of the electrodes during the discharge can be regarded as one of the main factors causing thermal contraction of the channel on the surface of electrodes, high-current density on the electrodes and enabling the independent existence of partial spots.
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We study a new Monte Carlo algorithm for generating self-avoiding walks with variable length (controlled by a fugacity) and fixed endpoints. The algorithm is a hybrid of local (BFACF) and nonlocal (cut-and-paste) moves. We find that the critical slowing-down, measured in units of computer time, is reduced compared to the pure BFACF algorithm: CPU N2.3 versus N3.0. We also prove some rigorous bounds on the autocorrelation time for these and related Monte Carlo algorithms.  相似文献   

4.
A new theory of rectangular coils without an iron core is described which amends the old one of Fabry and Bitter. It enables us to compute field intensities in coils having very small openings, which the old theory could not do.
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The paper describes a double-crystal monochromator unit. The influence of vertical divergence of the beam on the luminosity and degree of monochromatization is discussed in detail and experimentally proved. Finally, the author shows how to apply a double-crystal monochromator unit (using analyzing crystals of germanium (111)) in fluorescent X-ray emission analysis, especially for an X-ray quantometer.
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6.
Being formalized inside the S-matrix scheme, the zigzagging causility model of EPR correlations has full Lorentz and CPT invariance. EPR correlations, proper or reversed, and Wheeler's smoky dragon metaphor are respectively pictured in spacetime or in the momentum-energy space, as V-shaped, A-shaped, or C-shaped ABC zigzags, with a summation at B over virtual states |B B|. An exact correspondence exists between the Born-Jordan-Dirac wavelike algebra of transition amplitudes and the 1774 Laplace algebra of conditional probabilities, where the intermediate summations |B) (B| were over real hidden states. While the latter used conditional (or transition) probabilities (A|C) = (C|A), the former uses transition (or conditional) amplitudes A|C = C|A*. The formal parrallelism breaks down at the level of interpretation because (A|C) = |A|C|2. CPT invariance implies the Fock and Watanabe principle that, in quantum mechanics, retarded (advanced) waves are used for prediction (retrodiction), an expression of which is | U | = | U = U|, with | denoting a preparation, | a measurement, and U the evolution operator. The transformation | = |U or | = |U–1 exchanges the preparation representation and the measurement representation of a system and is ancillary in the formalization of the quantum chance game by the wavelike algebra of conditional amplitude. In 1935 EPR overlooked that a conditional amplitude A|C = A|BB|C between the two distant measurements is at stake, and that only measurements actually performed do make sense. The reversibility A|C = C|A* implies that causality is CPT-invariant, or arrowless, at the microlevel. Arrowed causality is a macroscopic emergence, corollary to wave retardation and probability increase. Factlike irreversibility states repression, not suppression, of blind statistical retrodiction—that is, of final cause.Dedicated to Professor David Bohm, proponent of the EPRB version of nonseparability.  相似文献   

7.
We investigate pair correlations in the two-dimensional Coulomb gas made up of two species of point ions carrying electric charges Z1 e(>0) and Z2 e(<0), and interaction by the logarithmic Coulomb potential. This system is known to be classically stable for couplings=e 2/k BTc=2/¦Z1Z2¦ (whereT is the temperature). Correlations between equally charged ions are shown to be greatly modified at short distances, in the range c/2<< c, due to gradual ion condensation. The usual integral equations for the pair correlation functions admit no solutions in that range. Preliminary Monte Carlo simulations for the symmetric case (Z1=–Z2) reveal a striking chemical equilibrium between tightly bound ion pairs and free ions, which is reasonably well described by a simple Bjerrum model.  相似文献   

8.
A delay-differential equationu(t)+u(t)=f(u(t–1)), 0t < , and its generalization are investigated in the limit 0, when the attractor's dimension increases infinitely. It is shown that a number of statistical characteristics are asymptotically independent of. As for the attractor, it can be regarded as a direct product ofO(1/) equivalent subattractors, their statistical characteristics being asymptotically independent of . The results enable one to predict some characteristics of the attractor with fractal dimensionD 1 for the case 1, when they are inaccessible numerically. The approach developed seems to be applicable for a wide class of spatiotemporal systems.  相似文献   

9.
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Betatron oscillations in an accelerator with a general field I
The paper gives a linear theory of equilibrium trajectories in an accelerator with a generalized magnetostatic field, the components of which are defined on a general rotation surface. Equations of motion of the particles in natural coordinates are derived with respect to the change in energy and dissipative force. A system of equilibrium trajectories is found in the general form. Conditions for the field components on the reference surface, necessary for the existence of equilibrium trajectories, for the conservation of their geometric similarities and for maintaining the constancy of the frequencies of the betatron oscillations, are derived. A condition is also derived which must be satisfied by the reference surface in order to conserve constant circular frequency of the particles. It is seen that it is not possible to find a field for an accelerator with an exactly constant circular frequency and with constant frequencies of the betatron oscillation in the relativistic energy region. An ultra-relativistic cyclotron with such properties is realizable.
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10.
Zusammenfassung Es wurde der Einfluß von Fremdstoffgehalt: auf die kritische Schubspannung 0, den Verfestigungskoeffizient A im BereichA der Verfestigungskurve; die Längea A des BereichsA, und die Schubspannung A am Ende des BereichsA, von Zinkeinkristallen untersucht. Es konnte gezeigt werden, daß der Einfluß von Fremdstoffgehalt auf den Wert der kritischen Schubspannung vorwiegend indirekter Natur ist. Die Abnahme des Verfestigungskoeffizienten mit zunehmendem Fremdstoffgehalt kann an Hand erhöhter Leerstellenkonzentration erklärt werden. Das Auftreten des BereichsB wird im Zusammenhang mit der Entstehung von Frankschen Halbversetzungen erwogen.
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Herrn P. Sirotek bin ich für den Umbau und die Instandsetzung des Polanyiaparates zu Dank verpflichtet. Mein Dank gehört ferner Herrn J. Voráek, für die präzise Durchführung der polarographischen Analysen, Frau I. Ejemová und M. Postránecká, für die Verrichtung der Orientierungsbestimmungen und Rechenarbeiten. Gleichzeitig möchte ich Frl. Svobodová meinen herzlichen Dank aussprechen — sie hat, auf Anregung des Lehrstuhls für mathematische Statistik an der mathematisch-physikalischen Fakultät der Karlsuniversität in Prag, mit großem Verständnis die statistische Auswertung der Meßergebnisse durchgeführt. Herrn Dr. F. Kroupa und Ing. B. esták bin ich für das Durchlesen des Manuskripts sowie wertvolle Hinweise zu Dank verpflichtet. Mein besonderer Dank für zahlreiche fruchtbare Diskussionen und Anregungen gilt Herrn P. Kratochvíl. Herrn Prof. Dr. A. Seeger danke ich ganz besonders für Kritik des Manuskripts und wertvolle Ratschläge.  相似文献   

11.
Three definitions of logical independence of two von Neumann latticesP1,P2 of two sub-von Neumann algebras 1, 2 of a von Neumann algebra are given and the relations of the definitions clarified. It is shown that under weak assumptions the following notion, called logical independence is the strongest:A B 0 for any 0 A P1, 0 B P2. Propositions relating logical independence ofP1,P2 toC *-independence,W * independence, and strict locality of 1, 2 are presented.  相似文献   

12.
We study the spectral properties of the Floquet operator for the periodically kicked HamiltonianH(t) =H 0+ + (tnT),H 0 being self-adjoint and pure point. We show that the Floquet operator is pure point for almost every , if is cyclic forH 0 and has absolutely convergent expansion in the basis of eigenstates ofH 0. When this last condition is not satisfied, the Floquet operator can have a continuous spectrum, as we show by an example.  相似文献   

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Zusammenfassung Es werden zwei Begriffe: Homogenität des Raumzeitkontinuums und Kovarianz der Gleichungen, wie sie in der Relativitätstheorie gebraucht werden, definiert und erläutert. Es wird gezeigt, doss die beiden Begriffe wesentlich verschieden sind und in Form nichtäquivalenter mathematischer Bedingungen ihren Ausdruck finden. Trotzdem werden beide Begriffe sowohl von Einstein, als auch in der Literatur über Relativitätstheorie mit einem und demselben Wort Relativität bezeichnet. Der Missgebrauch des Wortes Relativität bedeutet nicht nur einen terminologischen Fehler, sondern spricht auch von einem ungenügenden Verständnis der Grundidee der Relativitätstheorie, besonders der sog. allgemeinen Relativitätstheorie. Versteht man unter Relativität Homogenität des Raumes, so ist in der sog. allgemeinen Relativitätstheorie überhaupt keine Relativität vorhanden. Versteht man dagegen unter Relativität Kovarianz der Gleichungen, so steckt in jener Theorie nicht mehr Relativität, wie z. B. in den unrelativistischen Bewegungsgleichungen, welche ebensogut eine allgemein-kovariante Formulierung gestatten (Lagrangesche Gleichungen 2-ter Art). Die Bezeichnung allgemeine Relativitätstheorie ist daher irrefuhrend. Die geniale Theorie Einsteins ist eine reine Gravitationstheorie. , No 4, . 131, 1955. (RhilosophischeFragen No 4, S. 131, Moskau 1955. Ins Deutsche über setzt vom Verfasser).  相似文献   

16.
Velocities and other features of propagating fronts in the lattice-gas model analyzed by Bramsonet al. are computed by Monte Carlo simulation. The propagation velocity() is found to converge slowly to its asymptotic dependence on the exchange-rate parameter. The number density of occupied sites in the interaction zone (extending from the forwardmost occupied to the rearmost unoccupied site) appears to converge to 2/3 for large. Spatial profiles of site occupancy and interface number density for finite are compared to the profiles originally computed by Fisher using the differential equation obeyed in the large- limit. Several significant features inferred from the computations have not yet been explained analytically.  相似文献   

17.
Thermodynamic and structural properties of a hard spherocylinder fluid are calculated by means of the blip function theory byAndersen et al. and are compared with Monte Carlo simulation data. It is found that for spherocylinders of length-to-breadth ratio up to 3/2 the theory yields reasonably accurate results while for greater qualitative features of results may be correct only.  相似文献   

18.
Zusammenfassung An Einkristallen von Zn mit Beimengungen von Cd oder Cu wurde experimentell die Abhä agigkeit der Größe des Durchmessers der Fasersubstruktur vom Gehalt der Beimengungen untersucht, die aus der Theorie von Rutter und Chalmers [1] hervorgeht. Es wird die Möglichkeit gezeigt, die Größe des Verteilungskoeffizientenk aus den erzielten Ergebnissen abzuschätzen.
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19.
In their paper A note on Misunderstandings of Piron's Axioms for Quantum Mechanics, Foulis and Randall undertake a reply to our critique of Piron's question-proposition system (qp-s) which appeared in previous issues of this journal. In the present paper, we want briefly to refute the points of criticism raised by Foulis and Randall (FR). We argue that the misunderstandings are not ours, and we prove it.  相似文献   

20.
A nonzero 2-cocycle Z2(g, R) on the Lie algebra g of a compact Lie group G defines a twisted version of the Lie–Poisson structure on the dual Lie algebra g*, leading to a Poisson algebra C (g*()). Similarly, a multiplier c Z2(G, U(1)) on G which is smooth near the identity defines a twist in the convolution product on G, encoded by the twisted group C-algebra C*(G,c). Further to some superficial yet enlightening analogies between C (g*()) and C*(G,c), it is shown that the latter is a strict quantization of the former, where Plancks constant assumes values in (Z\{0})-1. This means that there exists a continuous field of C*-algebras, indexed by 0 (Z\{0})-1, for which A0= C0(g*) and A=C*(G,c) for 0, along with a cross-section of the field satisfying Diracs condition asymptotically relating the commutator in A to the Poisson bracket on C(g*()). Note that the quantization of does not occur for =0.  相似文献   

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